Spark plug having spark intensifying device therein



Jan. 1, 1935.

J. D. CURTIS SPARK PLUG HAVING SPARK INTENSIFYING DEVICE THERE IN Filed Jan. 28, 1932 FIG. B

FIG. A

JAMES D. C URTIS INVENTOR WW;

A TTORNEY Patented Jan. 1.1935

r 1, 9 86,624 p SPARK PLUGEHAVING SPARK INTENSIFYING 1 psvrcsrnsnsm v r James D. Curtis, Collin gswood, N. J assignor, by

Camden, NJ.

mesne assignments; to Helen Baus Curtis,

Application 'January 28. 1932, Serial No. 589,372

3 Claims. (01. 123169) i .The subject" of my invention is a spark plug for use with automobile or other internal combustion engines having a sparkintensifying device therein whereby a greatly improved spark is secured.

In general my device consists of a spark plug consisting of a porcelain insulatorhaving at one end thereof a terminal, a spring in contact with said terminal, an intensifying device comprising a plurality of elongated electric connecting elements mounted adjacent each other and adjacent the conducting elements of said spark intensifier, an inner electrode, a metallic shell surrounding said insulator and clamping it thereinand a ground electrode on said shell cooperating with said inner electrode.

One feature of my invention is the spark intensifying device which consists of an insulating casing having an axial perforation therethrough, metallic caps covering the ends of said casing, and rollers extending laterally through said casing and through the perforation therein so that their ends are adjacent said caps and their central portions are adjacent each other.

Another'ieature ofmy invention is that the shell is provided with a baffle of smaller internal diameter than the remainder of the shell so that a higher compression area is created adjacent the electrodes which form the spark gap.

Yet another feature of my invention is the provision of a ground electrode which extends for a considerable distance parallel to the central electrode which forms the opposite side of the spark gap. The ground electrode is of full cross section throughout said parallel portion.

For a further exposition of my invention ref? erence may be had to the annexed drawings and specification at the end whereof my. invention will be specifically pointed out and claimed. 1

In the drawing,

Fig. A is a sideelevation' of my device.

Fig. B is a vertical cross section through my device, and v Fig. C is a lateral cross section on line CC of Fig. A. 1 a

For the purposes of illustration in the drawing I have selected one embodiment which my invention may take. This embodiment consists of an electrode consisting of a terminal cap 1, and a threaded one piece terminal 2. The screw threads or other fastening means on, terminal 2 c'ooperate with threads on one end of an insulator 3 which is preferably made of porcelain.

The terminal 2 is preferably cemented at its.

screw'threads into insulator 3. Beneath termi nal 2 is provided a spring 4 which is shown as consisting of a relatively flat dish-shaped element having four prongs. I may, however, substitute a spring of any other shape or any convenient conducting material, such as metallic wool. l

Within a chamber in insulator 3 there is provided a spark intensifying device. This consists of a casing 6 of insulating material having an axial perforation or chamber 17. passing therethrough. At its opposite ends casing 6 carries metallic caps 5. Extending laterally through casing 6 and through the chamber 17 therein I provide rollers 7 of electric conduct-' ing material. Rollers 7 are mounted so that portions of their ends underlie portions of the caps 5 as is best seen from the lower roller 7 in Figure B. Rollers 7 are mounted in casing 6 so as to be adjacent to but out of contact with each other and so as tohave exceedingly limited movement relative to each other and to casing 6. Rollers 7 are shown as disposed at an angle to each other but they may be located parallel to each other but spaced apart with an opening between them.

Insulatorfi has its intermediate portion enlarged on its outer surface. This enlargement is secured between a metallic gland nut 8 and the 'metallic shell 9 which has screw threaded or other adjustable attachment to gland nut 8. Between gland nut 8 and insulator 3 there is interposed a gasket 11 and between a shoulder of shell 9 and insulator 3 there is interposed another gasket 13. By screwing up gland nut 8 and shell 9 insulator 3 is clamped therein betweengaskets 11 and 13.

Mounted in the lower. part of the chamber within insulator 3 is an inner electrode 10 which has contact with the lower cap 5 of. the spark gap .of appreciable length between electrodes 14and15. N

In its lower inner portion shell 9 has a baflle 16 of decreased diameter adjacent the spark gap between electrodes 14 and 15. This serves to furnish an area of increased pressure adjacent the spark gap so that the shock of the explosion does not enter the chamber" between the shell and the insulator inside the bafiie. This prevents cracking of the insulator at a point just beneath its point of contact with the shell.

I do not intend to be limited in the practice of my invention'save as the scope of the prior art and ofthe attached claims may require.

I claim:

1. In a spark plug including in combination an insulator having a chamber therein, a terminal mounted in said chamber at one end of said insulator, and a spring having contact with said terminal, a spark intensifier including in combination, a casing forming a partofsaid spark intensifier in said chamber and having an r axial perforation therethrough, metallic caps rollers mounted in said casing laterally and passing through the perforation therein so as to partially underlie said caps at their outer ends and to be located in'spaced relation in said perforation.

2. In a spark plug, a spark intensifying device comprising in combination, a casing of insulating material having an axial perforation therein, metallic caps overlying the perforated ends of said casing and overlying portions of the sides of said casing, and metallic rollers mounted for limited movement in said casing and projecting through the perforation therein, portions of the ends of said rollers underlying portions of said caps and the central portions of said rollers forming a spark gap within said casing between said rollers.

,3. The combination according to claim 2 in which the axes of the rollers are at right angles 'as seen in plan.

. JAMES D. CURTIS. 

